I freaking love this story. Granted there are a few minor spelling mistakes but we are only human but who ever said that your character is a Mary Sue is clearly jealous that they did not think to create this story themselves. Honestly, haters are gonna hate but don't let them get you down and please do not give up on this story.

I'm going to guess that this is your first attempt at writing in this fandom, since that's when most fanfic authors decide to 're-tell' the source material with an OC sibling or best friend. There's nothing wrong with creating an original character; however, completely re-writing the established canon in order to do so rarely goes over well with the fan base (especially when there's no new content added to the story other than the aforementioned OC). I understand authors' reasons for doing so, though:it's the easiest way to jump into fandom; but without proper attention to ALL the characters, not just the original, the previously established canon characters ultimately end up out-of-character, which can be a huge turn-off to the fans. Virginia was o-o-c from the very beginning, making her borderline unlikeable due to the complete personality shift, and it's hard to tell if that was an accident in the writing by trying to come up with sibling-like dialogue, or if it was intentional due to Angelica now being the main female protagonist (thus taking Virginia's place in the movie/show).

Your writing style is alright, but I suggest partnering with a beta reader who deals heavily in grammar and the more technical aspects of the craft. Your formatting is off, especially where dialogue proceeded/followed by character action is concerned, and the narrative is scattered quite a bit at times, making the story hard to follow; some sentences and paragraphs just plain don't make any sense (and that's coming from a T10K fan who knows the movie/show inside and out). There were also several places where the narrative shifted tense; usually the further you read into the chapter, and further into the story as a whole. A beta can help you fix any technical errors and tighten up your narrative before you post the chapters.

Also, I strongly recommend finding a T10K fan who can help you with all of the details during the editing process. There were quite a few errors that are horribly obvious to anyone who's extremely familiar with 'The 10th Kingdom.' For example: the advisor who accompanied Wendell to Snow White Memorial Prison was named Giles, not Childs; Blabberwort has orange hair, not reddish-pink; as well as a lot of mis-heard/written dialogue that makes no sense (such as 'free-roll dried herbs' instead of 'three year-old dried herbs'). Having someone to detail-check will not only help you stay as true to the source material as possible, especially when re-telling it, but they can also help with consistency when new dialogue and narrative are added to accommodate the OC.

By no means do I think you should give up, because I truly think you have potential. However, I WOULD love to see you branch out with a completely original story for the fandom other than simply re-hashing what was already brilliantly told by Simon Moore and the production team for Halmark and NBC. The Wendell/OC pairing is greatly under-served, and I think Angelica would thrive incredibly well as a character independent of Virginia and Tony.

Just some ideas to marinate on from a fellow writer. I wish you the best of luck. :)